Metallic bonding
Cambridge A-Level Chemistry (9701) · Unit 3: Chemical bonding · 9 flashcards
Metallic bonding is topic 3.3 in the Cambridge A-Level Chemistry (9701) syllabus , positioned in Unit 3 — Chemical bonding , alongside Electronegativity and bonding, Ionic bonding and Shapes of molecules. In one line: Metallic bonding is the electrostatic attraction between positive metal ions and delocalised electrons. These delocalised electrons are free to move throughout the metallic lattice, contributing to the metal's conductivity.
Marked as AS Level: examined at AS Level in Paper 1 (Multiple Choice), Paper 2 (AS Structured Questions) and Paper 3 (Advanced Practical Skills). The same content may also be assumed in Paper 4 (A Level Structured Questions).
The deck below contains 9 flashcards — 3 definitions and 6 key concepts — covering the precise wording mark schemes reward. Use the 3 definition cards to lock down command-word answers (define, state), then move on to the concept and calculation cards to handle explain, describe, calculate and compare questions.
Some cards in this deck are on other syllabus topics: 3.4 Covalent bonding and coordinate (dative covalent) bonding and 3.7 Dot-and-cross diagrams. Each card is labelled with its topic.
Metallic bonding
Metallic bonding is the electrostatic attraction between positive metal ions and delocalised electrons. These delocalised electrons are free to move throughout the metallic lattice, contributing to the metal's conductivity.
What the Cambridge 9701 syllabus says
2025-2027 syllabus, in our words · AS LevelWhat the syllabus expects you to be able to do in this topic, in plain English. For the exact wording, see the official syllabus (PDF).
- Define metallic bonding: it is electrostatic attraction between delocalised electrons and positive metal ions.
Also in this deck: 3.4 Covalent bonding and coordinate (dative covalent) bonding
- Define a covalent bond as the electrostatic attraction between a shared pair of electrons and the nuclei of the two atoms it joins. (a) Describe covalent bonding in molecules, which must include hydrogen (H₂), oxygen (O₂), nitrogen (N₂), chlorine (Cl₂), hydrogen chloride (HCl), carbon dioxide (CO₂), ammonia (NH₃), methane (CH₄), ethane (C₂H₆) and ethene (C₂H₄). (b) Understand that period 3 elements can expand their octet, including in sulfur dioxide (SO₂), phosphorus pentachloride (PCl₅) and sulfur hexafluoride (SF₆). (c) Describe coordinate (dative covalent) bonding, including in the ammonium ion, NH₄⁺, formed when gaseous ammonia reacts with gaseous hydrogen chloride, and in the Al₂Cl₆ molecule.
- (a) Describe covalent bonds as overlapping orbitals that give σ and π bonds: a σ bond forms when orbitals overlap directly between the two bonded atoms, and a π bond forms when neighbouring p orbitals overlap sideways, so the overlap lies on either side of the σ bond (above and below it). (b) For molecules including N₂, HCN, C₂H₄, C₂H₆ and H₂, describe the way their σ and π bonds are formed. (c) Describe sp, sp² and sp³ orbitals using the idea of hybridisation.
- (a) Define bond energy (the energy needed to break one mole of a given covalent bond, with the species in the gas phase) and bond length (the distance between the nuclei of two atoms joined by a covalent bond). (b) Compare how reactive covalent molecules are, using bond energy values and the idea of bond length.
Also in this deck: 3.7 Dot-and-cross diagrams
- Draw dot-and-cross diagrams of coordinate, covalent and ionic bonding, covering every compound named in 3.4 and 3.5; the species drawn may have an odd number of electrons or contain an atom with an expanded octet.
Cambridge syllabus keywords to use in your answers
These are the official Cambridge 9701 terms tagged to this section. Mark schemes credit responses that use the exact term — weave them into your answers verbatim rather than paraphrasing.
Tips to avoid common mistakes in these topics
- › Always label metallic structures clearly with 'cations' or 'positive ions' and 'delocalised electrons' to secure full marks.
- › Specify the exact atomic orbitals involved in hybridisation, such as the sp hybridised orbitals of nitrogen in the N2 molecule.
- › Describe hybridisation as the mixing of atomic orbitals of similar energies to form a new set of equivalent hybrid orbitals.
- › Count all single bonds and one bond from every double/triple bond as sigma bonds; ensure every C-H bond is included.
- › Use the exact syllabus definition: covalent bonding is the electrostatic attraction between two nuclei and a shared pair of electrons.
Topic 3.3 · Metallic bonding
Define metallic bonding.
Metallic bonding is the electrostatic attraction between positive metal ions and delocalised electrons. These delocalised electrons are free to move throughout the metallic lattice, contributing to the metal's conductivity.
Topic 3.3 · Metallic bonding
Describe the structure of a typical metallic lattice.
A metallic lattice consists of a regular arrangement of positive metal ions surrounded by a 'sea' of delocalised electrons. These electrons are not associated with any single atom.
Topic 3.3 · Metallic bonding
How does the charge and radius of a metal ion affect the strength of metallic bonding?
Higher charge density (higher charge and/or smaller ionic radius) leads to stronger electrostatic attraction between the metal ions and delocalised electrons, thus stronger metallic bonding.
Topic 3.4 · Covalent bonding and coordinate (dative covalent) bonding
Define covalent bonding.
Covalent bonding is the electrostatic attraction between the nuclei of two atoms and a shared pair of electrons. These shared electrons are attracted to both positive nuclei, holding the atoms together.
Topic 3.7 · Dot-and-cross diagrams
Draw a dot-and-cross diagram to show the covalent bonding in a molecule of oxygen, O2.
O2 contains a double covalent bond with each oxygen atom sharing two electrons, so that each oxygen atom achieves a stable octet of electrons in its outer shell.
Topic 3.4 · Covalent bonding and coordinate (dative covalent) bonding
Explain how elements in Period 3 can expand their octet.
Period 3 elements, such as sulfur and phosphorus, can expand their octet because they have available d-orbitals that can accommodate additional electrons, allowing them to form more than four covalent bonds. Examples include SF6 and PCl5.
Topic 3.4 · Covalent bonding and coordinate (dative covalent) bonding
Define coordinate (dative covalent) bonding.
Coordinate bonding occurs when one atom provides both electrons for the shared pair in the covalent bond. The resulting bond is essentially the same as a normal covalent bond, but its formation differs.
Topic 3.4 · Covalent bonding and coordinate (dative covalent) bonding
Describe the formation of the ammonium ion (NH4+) using a coordinate bond.
Ammonia (NH3) donates its lone pair of electrons to a proton (H+) to form NH4+. The bond between the nitrogen and the newly attached hydrogen is a coordinate bond, as both electrons originate from the nitrogen atom.
Topic 3.4 · Covalent bonding and coordinate (dative covalent) bonding
Describe the bonding in aluminium chloride dimer (Al2Cl6).
Aluminium chloride exists as a dimer, Al₂Cl₆. In AlCl₃ the aluminium has only 6 outer electrons. In the dimer, a chlorine atom of each AlCl₃ unit donates a lone pair to the aluminium atom of the other unit, forming two coordinate (dative) bonds in total. Each aluminium then has 4 bonds and 8 outer electrons, arranged tetrahedrally.
More Chemistry flashcards
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All Chemistry FlashcardsMore topics in Unit 3 — Chemical bonding
Metallic bonding sits alongside these A-Level Chemistry decks in the same syllabus unit. Each uses the same spaced-repetition system, so progress in one informs the next.
Key terms covered in this Metallic bonding deck
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